Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), estimate positions of vehicles based on signals from earth-orbiting satellite transmitters. For accuracy and reliability reasons, these systems have traditionally not been used for critical phases of aircraft navigation and guidance, such as aircraft landings. However, recent years have seen the development of ground-augmented GPS systems for use in automatic landing systems, such as a GNSS Landing System (GLS). These augmented systems rely on broadcast correction data to correct position estimates, or solutions, and thus provide more accurate position solutions.